In this project we will examine two areas of physiology of eccrine sweating in man. The first area is related to temperature regulation; we propose to identify and quantitate those changes in the sweating control system which accompany work training and heat acclimatization. The second area is related to the pathophysiology of atopic disease; to better define differences between the sweating responses of normal subjects and those with atopic disease to local cholinergic and adrenergic stimulation and blockade. Techniques to be used in these studies should allow the identification of physiological sites of adaptation in heat acclimatization and to determine whether or not an adrenergic beta-receptor defect in the sweat glands is diagnostic for atopy. Two practical outcomes of these studies might be the development of screening tests (non-invasive) for distinguishing atopic from other dermatitis and allergic from vasomotor rhinitis and for assessing heat tolerance or potential for acclimatization in military recruits or others who might have to suddenly shift from temperate to tropical or desert climes and in those who must limit their heat exposure, such as patients recovering from serious cardiac disease.